According to Vertical Systems Group, customer installations of carrier-based frame relay services in 1991 consisted of 120 ports worldwide. By 2001, the number of ports had increased to approximately 1.78 million. Providers often route frame relay services over asynchronous transfer mode (ATM) backbones. According to the ATM Forum (www.atmforum.com), approximately eighty percent of the world's telecommunications service providers use ATM in the core of their networks. As the number of customer and network installations has increased, so has the difficulty of effectively and efficiently monitoring and managing the networks supporting the providers' customers.
Communication through frame relay or ATM networks occurs within a logical path called a virtual circuit. The virtual circuit may be a permanent or switched virtual circuit. Out of the frame relay or ATM network, there are physical circuits that eventually connect to customer premises equipment (CPE) or the like. When a problem within a network arises, most of the Regional Bell Operating Companies (RBOCs) use well known out-of-the-box solutions to perform remote physical layer testing in an attempt to determine the source of the problem. Such out-of-the-box solutions perform physical layer tests remotely by sending a command to a network element and receiving a response, and, based on the response from the network element, creating a loop to test the physical circuit and determine whether it is working properly or not. However, in creating and testing a loop between points A and B, there is no way to determine what is occurring at the logical layer. Thus, if the network problem is in the logical portion of the frame relay or ATM network, physical layer testing cannot determine where the problem lies.
Presently, no cost effective remote logical layer testing solutions exist. Logical layer testing generally requires connecting a logical test box to a physical circuit to determine logical layer information. For example, several companies, such as Acterna (and formerly TTC), Hekemian Labs, Hewlett Packard, and others well known to those skilled in the art, provide logical test boxes, that is, physical test pads with logical cards, that enable users to gain physical access to the circuit with the test pad and determine what is occurring at the logical level of the circuit using the logical card. A logical test box is physically connected to a circuit either through direct connection (i.e., the logical test box is placed in series with the physical circuit) or by using a digital cross-connect system (DCS) to gain access to the physical layer of the circuit. A DCS provides physical access to multiple circuits and is well known to those skilled in the art. Thus, in other words, existing methods of logical layer testing require connecting a logical test box everywhere that a physical circuit or digital cross-connect exists. This requires manual connection of the logical test box to the physical circuit in order to test the logical layer or gather logical layer information.
The price of a logical test box may be anywhere from $100,000 to $1,000,000. Typically, a logical test box only works with up to three digital cross-connects (DCSs). For example, the Atlanta metropolitan area, which is one local access transport area (LATA), includes approximately eighty DCSs, meaning that approximately twenty-five to thirty logical test boxes would be required for logical layer testing in the Atlanta LATA alone.
Accordingly, there is a need for methods and systems of obtaining logical layer information at a reduced cost to telecommunications service providers and without the use of numerous logical test boxes that require physical connection to a circuit.